90 merc ignition woes

[Bobby Powell]

I have a '84 90 hp mercury that fails to produce any spark no matter what I try.<br /><br />I ohm tested the staor and it failed so I replaced the stator and still not getting the proper voltage at cranking speed. blue leads are getting 5.6 volts at cranking speed and they should be 200+ volts DC. <br /><br />I replaced the ignition switch since the push to choke was hard to activate. now te push to choke works when depressed, the volt gauge shows voltage from the battery when in the run position, and the engine turns over when turned to the start position. <br /><br />I am at a stand still...I figure if the ignition switch, stator, and battery are new then I should at least get the proper voltage from the stator before it goes to the powerpacks. <br /><br />I have disconnected the mercury tilt switch on the side of the engine block thinking this is causing it...no luck!??

<br /><br />Could it be a bad engine harness connector? What leads should have continuity when the ignition is in the run position?<br /><br />There is no kill switch but there is a nuetral start switch that wont allow the starter to turnover unless it is in nuetral.<br /><br />Anyone outthere that can hint me in the right direction on solving this woe of mine will be e-mailed a cold one...uhhh...as soon as I figure out how..any ideas? jk<br /><br />Thanks in advance and sorry about the long post-<br /><br />Bobby Powell

 

[ODDD1]

Re: 90 merc ignition woes

OK, bobby , lets see if we can get you out of the woods....about the stator..did new one pass the ohms test? if yes take your voltmeter and ckeck for voltage on the blue wires when they are UNHOOKED from the switch boxes.....got voltage now? That means one or both of switch boxes is bad...if no voltage is there[unhooked] then take that POS back where you bought it...<br />All the key switch wiring/boat wiring does to kill the ignition is make a ground connection to the black/yell wire on the switch boxes..unhook the 2 blk/yell wires on the switch boxea to eliminate all wiring outside the ignition system....

 

[Bobby Powell]

Re: 90 merc ignition woes

Oddd1:<br />I did the ohms test on the new stator and it passes. I then did what you said, unhooked the black /yellow wires from the switch box, and then unhooked the blue leads from the switch box and attached my volt meter to them. Cranked over engine and.....no voltage. I think it is time I shell out some money and put this bad boy in the shop. Thanks for all your help ODDD1. There is only but so much that can be done without you visually seeing the motor.<br /><br />Bobby Powell

 

[ODDD1]

Re: 90 merc ignition woes

Amen, Bob.my magic wand only works when i can touch the motor....LOL

 

[Bobby Powell]

Re: 90 merc ignition woes

Good news! I bought 2 used switch boxes and whoala...spark! bought new fuel, added oil, prayed and hoped carbs were not gunked up, and...yup....she started! <br /><br />I have not put her in the water yet. <br /><br />With the motor running I was pulling the plug wires off (to verify good spark) on the individual cylniders I found that the #3 cylnider plug wire did not hae as much juice. I mean, I could not hear the spark arcing and feeling the shock like the others. And by listening to the motor it did not seem to have as much affect by discconceting the plug wire as the rest of 'em. What is strange is that the rpms dropped down about 100 rpm's for all 6 cylinders when pulling off the individual plug wires. should I go by the RPM gauge or by the jolt of electricity? There is some arcing of spark but nnot just as much as the others.<br /><br />Could this be a bad switchbox( I have a 30 day warranty) or does this sound ok. I changed the coils and wires to try to isolate bot problem stayed with cylnder.<br /><br />Thsnk y'll-<br />Bobby